Buggy code:
public class AjaxRequestTarget implements IRequestTarget { public static interface IListener { public void onBeforeRespond ( Map map , AjaxRequestTarget target ) { } public void onAfterRespond ( Map map , AjaxRequestTarget . IJavascriptResponse response ) { } } public static interface IJavascriptResponse { public void addJavascript ( String script ) { } } private final class AjaxResponse extends WebResponse { private final AppendingStringBuffer buffer = new AppendingStringBuffer ( 256 ) ; private boolean escaped = false ; private final Response originalResponse ; public AjaxResponse ( Response originalResponse ) { } public CharSequence encodeURL ( CharSequence url ) { } public CharSequence getContents ( ) { } public OutputStream getOutputStream ( ) { } public boolean isContentsEncoded ( ) { } public void reset ( ) { } public void write ( CharSequence cs ) { } } private static final Log LOG = LogFactory . getLog ( AjaxRequestTarget . class ) ; private final List appendJavascripts = new ArrayList ( ) ; private final AjaxRequestTarget . AjaxResponse encodingBodyResponse ; private final AjaxRequestTarget . AjaxResponse encodingHeaderResponse ; private final Map markupIdToComponent = new LinkedHashMap ( ) ; private final List prependJavascripts = new ArrayList ( ) ; private List listeners = null ; public AjaxRequestTarget ( ) { } public void addListener ( AjaxRequestTarget . IListener listener ) { } public final void addChildren ( MarkupContainer parent , Class childCriteria ) { } public final void addComponent ( Component component ) { } public final void addComponent ( Component component , String markupId ) { if ( Strings . isEmpty ( markupId ) ) { throw new IllegalArgumentException ( "markupId<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>empty" ) ; } if ( component == null ) { throw new IllegalArgumentException ( "component<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>null" ) ; } else if ( component instanceof Page ) { throw new IllegalArgumentException ( "component<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>a<seq2seq4repair_space>page" ) ; } else if ( component instanceof AbstractRepeater ) { <START_BUG> throw new IllegalArgumentException ( ( ( "Component<seq2seq4repair_space>" + ( component . getClass ( ) . getName ( ) ) ) + "<seq2seq4repair_space>has<seq2seq4repair_space>been<seq2seq4repair_space>added<seq2seq4repair_space>to<seq2seq4repair_space>the<seq2seq4repair_space>target.<seq2seq4repair_space>This<seq2seq4repair_space>component<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>repeater<seq2seq4repair_space>and<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>repainted<seq2seq4repair_space>via<seq2seq4repair_space>ajax<seq2seq4repair_space>directly.<seq2seq4repair_space>Instead<seq2seq4repair_space>add<seq2seq4repair_space>its<seq2seq4repair_space>parent<seq2seq4repair_space>or<seq2seq4repair_space>another<seq2seq4repair_space>markup<seq2seq4repair_space>container<seq2seq4repair_space>higher<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>hieararchy." ) ) ; <END_BUG> } markupIdToComponent . put ( markupId , component ) ; } public final void addJavascript ( String javascript ) { } public final void focusComponent ( Component component ) { } public final void appendJavascript ( String javascript ) { } public void detach ( final RequestCycle requestCycle ) { } public boolean equals ( final Object obj ) { } public int hashCode ( ) { } public final void prependJavascript ( String javascript ) { } public final void respond ( final RequestCycle requestCycle ) { } private void fireOnBeforeRespondListeners ( ) { } private void fireOnAfterRespondListeners ( final WebResponse response ) { } private void respondComponents ( WebResponse response ) { } public String toString ( ) { } protected String encode ( String str ) { } protected String getEncodingName ( ) { } protected boolean needsEncoding ( String str ) { } private void respondComponent ( final Response response , final String markupId , final Component component ) { } private class AjaxHeaderResponse extends HeaderResponse { private static final long serialVersionUID = 1L ; private void checkHeaderRendering ( ) { } public void renderCSSReference ( ResourceReference reference , String media ) { } public void renderCSSReference ( String url ) { } public void renderCSSReference ( String url , String media ) { } public void renderJavascript ( CharSequence javascript , String id ) { } public void renderCSSReference ( ResourceReference reference ) { } public void renderJavascriptReference ( ResourceReference reference ) { } public void renderJavascriptReference ( String url ) { } public void renderString ( CharSequence string ) { } public AjaxHeaderResponse ( ) { } public void renderOnDomReadyJavascript ( String javascript ) { } public void renderOnLoadJavascript ( String javascript ) { } public Response getResponse ( ) { } } private boolean headerRendering = false ; private HtmlHeaderContainer header = null ; private IHeaderResponse headerResponse ; public IHeaderResponse getHeaderResponse ( ) { } private static class AjaxHtmlHeaderContainer extends HtmlHeaderContainer { private static final long serialVersionUID = 1L ; public AjaxHtmlHeaderContainer ( String id , AjaxRequestTarget target ) { } protected IHeaderResponse newHeaderResponse ( ) { } private transient AjaxRequestTarget target ; } private void respondHeaderContribution ( final Response response , final Component component ) { } private void respondInvocation ( final Response response , final String js ) { } }

Fix:
throw new IllegalArgumentException ( ( ( "Component<seq2seq4repair_space>" + ( component . getClass ( ) . getName ( ) ) ) + "<seq2seq4repair_space>has<seq2seq4repair_space>been<seq2seq4repair_space>added<seq2seq4repair_space>to<seq2seq4repair_space>the<seq2seq4repair_space>target.<seq2seq4repair_space>This<seq2seq4repair_space>component<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>repeater<seq2seq4repair_space>and<seq2seq4repair_space>cannot<seq2seq4repair_space>be<seq2seq4repair_space>repainted<seq2seq4repair_space>via<seq2seq4repair_space>ajax<seq2seq4repair_space>directly.<seq2seq4repair_space>Instead<seq2seq4repair_space>add<seq2seq4repair_space>its<seq2seq4repair_space>parent<seq2seq4repair_space>or<seq2seq4repair_space>another<seq2seq4repair_space>markup<seq2seq4repair_space>container<seq2seq4repair_space>higher<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>hierarchy." ) ) ;